How to set borderstyle of a datagridview column at runtime (.Net Framework 4.0)?

I have a readonly datagridview that is bound to a datasource. It has two columns. Now I want the first column to have no cell borderstyle; and the second one to have 'All' (i.e. all sides of the cell shall have a border) as cell borderstyle. Before binding the datagridview to the datasource, I'm writing something like mentioned below but it's taking no effect. Assume the column in question is named DisplayName.